Running, particularly jogging, has become a widespread phenomenon. With the onset of this phenomenon, more attention has been paid to the mechanics of and equipment for running. For example, significant developments and improvements have been made during the past five to ten years with regard to running shoes, lightweight and breathable shirts and shorts, as well as lightweight and protective outer gear.
In the typical running motion, the arms of an individual runner alternately swing back and forth. With regard to most runners, particularly recreational runners, the arms do not swing in relaxed, perfect synchronization with legs and respiratory system. Inefficient expenditure of energy is a result; more particularly, the arms themselves tend to become quite tired and to lose suppleness. In fact, general fatigue results from this situation because arm muscles must always be tense to maintain the hands in an elevated position. This leads to a build-up of lactic acid in the muscles and bloodstream that drains oxygen from the bloodstream to convert it to glycogen. Fatigue is the primary problem when long distances are run.
To solve the problems of tired arms as well as general fatigue, a device was developed to allow the arms to swing naturally while running, without the usual tension in the biceps, deltoids, shoulder and chest interface muscles. The device developed consisted of a shirt having hanging therefrom two strap loops, one for each arm. The strap loops were intended to confine the motion of each swinging arm to a more natural, continuous motion close to the body as well as to provide support for each arm, in effect transferring the tension of the arms to the strap loops. Another advantage of this device was that runners who used the shirt tended thereafter to swing their arms in a more natural motion when the shirt wasn't used. The natural motion of arms, when allowed to swing automatically, is continuous and somewhat elliptical in path.
In the device developed, each strap loop was attached by stitches, rivets, and the like, directly to a point adjacent to the respective side of the neck opening. However, a significant difficulty with this arrangement was that the point of attachment tended to tear or separate, often unexpectedly, after short periods of use. Also, the points of attachment could be uncomfortable, and, since the strap loops were integrally attached to the shirts, the shirts were not readily washable in standard washing machines. Furthermore, the shirts were not versatile because they did not permit the runner the option of attaching or removing the straps.